Pressure-gage.



G. J. MANNING.

PRESSURE GAGE.

APPLIOATION FILED JAN. 26, 1909.

957,471 Patented May 10, 1910.

I I [1114! Ill [11% /IZM 5 N o #0 N m N it g fizz-M572 for aozenz @72 J. Fianna 12g COLEMAN J. MANNING, or MEDFORD,

STEAM GAUGE AND VALVE MANUFACTURING COMPANY,

MASSACHUSETTS, ASSIGNOR TO AMERICAN F BOSTON, IMASSAGHU- SETTS, A. CORPORATION OF NEW J ERSEY PRESSURE-GAGE.

Specification of Letters Patent.

Application filed January 26, 1909. Serial No.

Patented May 10, 1910. 474,236.

To all whom, it may concern: I

Be it'known that I, COLEMAN J. MANNING, of Medford, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Pressure-Gages, of which the following is a specificatlon.

' steam or other plify sents a front elevation of embodying my invention,

't-ion from the Bourdon tube '16 attached to This invention relates to -a pressure gage employing a tubular spring or Bourdon tube of curved form, one end of the tube being fixed, and communicating with a source of pressure, while the opposite end of the tube is free, and is adapted tobe moved laterally outward byan increase of pressure tending to straighten the tube, and to be moved laterally inward by the resilience of the tube when the pressure decreases.

The invention hasifor its object to simthe construction and increase the durability of a gage of this character, articularly as regards the mechanism WlllClflInparts rotary movement from the free end of the tube to a shaft j ournaled in the casing of the gage and carrying apointer which is caused to move over the dial of the gage by expanding and contracting movements of thetube. 1

The invention consists in the improvements which I will now proceed to describe and claim.

Of the accompanying drawings, forming a part of this specification,-Figure 1 reprea pressure gage a portion of the removed. Fig. 2 represents a seclne 22 of Fig. 1. Fig. 3 repredial bein tion on sents a side view of the ports the pointer shaft, and the mechanism supported by said bracket for imparting moto the pointer.

The same reference characters indicate the same parts in all the figures.

In the drawings, 12 represents the casing of the gage, which is preferably ofcircular form, and is provided with a suitable dial 13 over which a pointer 14 is movable by movements of the Bourdon tube imparted through connecting mechanism to the shaft of the pointer, as hereinafterfdescribed.

15 represents the Bourdon tube, the inner end of which is aflixed to a chambered socket the casing 12, and receives pressure from steam admitted to said socket through an inlet fitting 17.

bracket which sup- I The tube 15 is' elongated and bent to form a spiral which preferably has the number of convolutions shown in Fig. 1, the tube being of much greater length than the ordinary Bourdon tube, which is formed into a single loop, and does not have a spiral formation. I

- 18 represents an arm positively secured byscrews 19 and 20to afiattened ear formed on the free end of the tube 15, the screw 20 passing through a segmental slot 21 in the arm 18. Said screw 20 and slot 21 permit the. arm to be adjusted by swinging it on the screw 19, when the screw 20 is loosened, to vary the radial distance between a pin 22 aflixed to the outer end of the arm 18, and the shaft or arbor 23 which carries the pointer let.

24represents a bracket which is aflixed by screws 25 to the socket 16, and overhangs the central portion of the space surrounded by the Bourdon tube 15. The pointer shaft 23 is journaled in a bearing in the outer end of the bracket 24, and is provided with a pinion 26 located at the under side of the bracket.

27 represents a lever which is pivoted at 28 to the bracket 24, and has at the outer end of one of its arms a segmental rack 29 meshing with the pinion 26.- In the other arm of the lever 27 is a longitudinal slot 30 which receives the stud 22 on the arm 18.

The free end of the Bourdon tube 15 is moved outwardly from the center of the easing by an increase of pressure, and is moved inwardly by the resilience of the tube when the pressure decreases. The elongation and spiral formation of the tube causes a much greater amplitude of movement of its free end than would occur if the tube had but one The movements of the free loop, asusual.

are imparted by-the arm 18 end of thetube to the lever 27 which is oscillated on its pivot 28, and imparts through the segmental rack 9 and pinion 26 rotary movements to the pointer shaft 20, -the pointer being thus moved over .the dial. The amplitude of movement of the free end of the tube 15 enables all the required movements'to be imparted to the pointer 14 by the simple mechanism above described, said mechanism including the arm '18, the lever 27, with its rack s ment 29, and the pinion 26.

The ever 27 is oscillated through a sufiiciently wide arc to enable its teeth to be objectionably rapid wear of said teeth;

The improved gage above described is intended particularly for traction engines, the operation of which is attended with considerable jar and vibration. Ordinarily, pressure gages used on engines of this character have been short-lived, so far as the mechanism for mommunicating motion from the Bourdon tube to the pointer is concerned, owing to the fact that the tube is usually composed of a single loop, so that the movements of its free end are relatively short- It has, therefore, been necessary to provide motion multiplying mechanism between the free end of the spring and the lever carrying the rack segment engaging the pinion on the pointer shaft. It has also been necessary to provide a relatively larger number of teeth on the rack segment, and to make the teeth correspondingly small in order that a su cient number may be formed in a segment of the greatest length practicable. It has been found, therefore, that pressure gages applied to traction engines have occasioned more or less trouble owing to the rapid wear of the gear teeth and of the joints of the motion multiplying mechanism through which motion is communicated from the free end of heavy and durable, the

plitude signature, in

the spring to the. lever carrying the rack segment. I-hese objections are obviated by the improvements above described, the amof movement of the free end of the spring enabling the motion communicating mechanism to be reduced to the smallest number'of parts, and the gear teeth to be made relatively heavy, and durable.

I claim:

In a pressure gage, the combinationof a casing having a steaminlet, a Bourdon tube, the inner end of which is afliXed to the easing and communicates with said inlet, the tube being of spiral form, whereby its free end is given a maximum amplitude of movement, a fixed support overhanging the central portion of the space surrounded by said tube, and provided with an enlargement forming a bearing, a pointer-carrying arbor journaled in said bearing and provided with a pinion, said bearing serving as the sole support for said arbor, a fulcrum screw also secured to said support at a point located perpendicularly below said bearing, a twoarmed lever mounted on said fulcrum screw and having on one arm a segmental rack engaging said pinion, the other arm of said lever having a longitudinal slot, an arm pivotally connected to the free end of the spiral tube and having a stud'projecting into the slot of said lever, and means forpreventing pivotal movement of said arm.

In testimony whereof I have aflixed my resence of two witnesses.

OLEMAN J. MANNING. Witnesses C. F. BROWN, P, PEZZETTI. 

